Joint construction of cobalt-based alloy

Abstract

In the joint construction of cobalt-based alloy, a cobalt-based alloy layer 1 , in which granular or massive eutectic carbide 2 disperses, is joined to a metal of a base metal 37 via an insert metal layer 36 . For the joint construction of cobalt-based alloy, liquid phase diffusion bonding is performed at a temperature of 1100° C. for a retention time of 1 hour with an insert metal with a thickness of about 40 μm being interposed between the base metal, which is S45C carbon steel, and a cobalt-based alloy material which has granular or massive eutectic carbide with a grain size not larger than 30 μm in a matrix of cast structure and contains 1.03 wt % C, 29.73 wt % Cr, 3.86 wt % W, 2.59 wt % Ni, 2.67 wt % Fe, 0.59 wt % Si, and 0.07 wt % Mo, the balance substantially being Co. The cobalt-based alloy layer 1 after bonding contains granular or massive eutectic carbide.

1. A joint construction of cobalt-based alloy in which a cobalt-based alloy material portion is diffusion bonded to a base metal portion by interposing an insert metal between said cobalt-based alloy portion, in which granular or massive eutectic carbide disperses in a matrix of metal microstructure, and said base metal portion, wherein
 a layer which has an element of said insert metal is formed over said base metal portion, and said cobalt-bases alloy portion is located over said layer.  
 
     
     
       2. The joint construction of cobalt-based alloy according to  claim 1 , wherein said base metal portion and said cobalt-based alloy portion contain an element diffused from said insert metal. 
     
     
       3. The joint construction of cobalt-based alloy according to  claim 2 , wherein said insert metal layer contains an element diffused from said base metal portion and cobalt diffused from said cobalt-based alloy portion. 
     
     
       4. The joint construction of cobalt-based alloy material according to  claim 3 , wherein the grain size of said eutectic carbide is not larger than 30 μm. 
     
     
       5. The joint construction of cobalt-based alloy material according to  claim 3 , wherein said base metal portion is a material selected from the group consisting of carbon steel, low alloy steel, and stainless steel. 
     
     
       6. The joint construction of cobalt-based alloy material according to  claim 5 , wherein said cobalt-based alloy portion contains 0.6 to 3% C, 2% or less Si, 25 to 32% Cr, 15% or less W, 0 to 3% Fe, 0 to 3% Ni, and 0 to 6% Mo by weight, the balance being Co and unavoidable impurities. 
     
     
       7. The joint construction of cobalt-based alloy material according to  claim 3 , wherein said cobalt-based alloy portion contains 0.6 to 3% C, 2% or less Si, 25 to 32% Cr, 15% or less W, 0 to 3% Fe, 0 to 3% Ni, and 0 to 6% Mo by weight, the balance being Co and unavoidable impurities. 
     
     
       8. The joint construction of cobalt-based alloy material according to  claim 2 , wherein the grain size of said eutectic carbide is not larger than 30μm. 
     
     
       9. The joint construction of cobalt-based alloy material according to  claim 2 , wherein said base metal portion is a material selected from the group consisting of carbon steel, low alloy steel, and stainless steel. 
     
     
       10. The joint construction of cobalt-based alloy material according to  claim 2 , wherein said cobalt-based alloy portion contains 0.6 to 3% C, 2% or less Si, 25 to 32% Cr, 15% or less W, 0 to 3% Fe, 0 to 3% Ni, and 0 to 6% Mo by weight, the balance being Co and unavoidable impurities. 
     
     
       11. The joint construction of cobalt-based alloy according to  claim 1 , wherein said insert metal layer contains an element diffused from said base metal portion and cobalt diffused from said cobalt-based alloy portion. 
     
     
       12. The joint construction of cobalt-based alloy material according to  claim 11 , wherein the grain size of said eutectic carbide is not larger than 30 μm. 
     
     
       13. The joint construction of cobalt-based alloy material according to  claim 11 , wherein said base metal portion is a material selected from the group consisting of carbon steel, low alloy steel, and stainless steel. 
     
     
       14. The joint construction of cobalt-based alloy material according to  claim 13 , wherein said cobalt-based alloy portion contains 0.6 to 3% C, 2% or less Si, 25 to 32% Cr, 15% or less W, 0 to 3% Fe, 0 to 3% Ni, and 0 to 6% Mo by weight, the balance being Co and unavoidable impurities. 
     
     
       15. The joint construction of cobalt-based alloy material according to  claim 13 , wherein said cobalt-based alloy portion contains 0.6 to 3% C, 2% or less Si, 25 to 32% Cr, 15% or less W, 0 to 3% Fe, 0 to 3% Ni, and 0 to 6% Mo by weight, the balance being Co and unavoidable impurities. 
     
     
       16. The joint construction of cobalt-based alloy material according to  claim 1 , wherein the grain size of said eutectic carbide is not larger than 30 μm. 
     
     
       17. The joint construction of cobalt-based alloy material according to  claim 16 , wherein said base metal portion is a material selected from the group consisting of carbon steel, low alloy steel, and stainless steel. 
     
     
       18. The joint construction of cobalt-based alloy material according to  claim 16 , wherein said cobalt-based alloy portion contains 0.6 to 3% C, 2% or less Si, 25 to 32% Cr, 15% or less W, 0 to 3% Ni, and 0 to 6% Mo by weight, the balance being Co and unavoidable impurities. 
     
     
       19. The joint construction of cobalt-based alloy material according to  claim 1 , wherein said base metal portion is a material selected from the group consisting of carbon steel, low alloy steel, and stainless steel. 
     
     
       20. The joint construction of cobalt-based alloy material according to  claim 1 , wherein said cobalt-based alloy portion contains 0.6 to 3% C, 2% or less Si, 25 to 32% Cr, 15% or less W, 0 to 3% Fe, 0 to 3% Ni, and 0 to 6% Mo by weight, the balance being Co and unavoidable impurities.